Once-through multi-pass steam generator

Abstract

The utility model belongs to the technical field of steam generator, especially a crossflow multi-return stroke steam generator, including the hollow smoke sealing cylinder, the smoke sealing cylinder upper end is equipped with the steam collecting ring, the lower end is equipped with the water collecting ring, is equipped with the annular heat exchange pipe group formed by the heat exchange pipe of many roots in the smoke sealing cylinder, and leaves the smoke gap between two adjacent heat exchange pipes, the heat exchange pipe upper end intercommunication steam collecting ring, the lower end intercommunication water collecting ring, the smoke sealing cylinder middle part is equipped with the baffle horizontally, and the baffle edge is connected on the outside wall on each heat exchange pipe, and the inside space of annular heat exchange pipe group is divided into the low temperature convection zone and high temperature hearth zone distributing up and down, the low temperature convection zone is located high temperature hearth zone top. The utility model can effectively prevent the heat exchange pipe from the heat transfer deterioration and lead to overburning damage.

Description

Technical Field

[0001] This utility model belongs to the field of steam generator technology, and specifically refers to a cross-flow multi-pass steam generator. Background Technology

[0002] Once-through steam generators are not classified as special equipment and are not subject to inspection, saving inspection costs. They are also small in size and light in weight, do not require a separate equipment room, and are flexible and unrestricted in installation. They are often used to replace traditional steam boilers and do not require a full-time boiler operator with a boiler operator's license. They are suitable for steam-using fields such as textile printing and dyeing, wineries, bean product processing, and hotels.

[0003] Traditional through-flow steam generator heat exchange tubes are located in the high-temperature radiation zone of the furnace from the heat absorption section to the evaporation section. When the steam approaches saturation, the heat transfer coefficient is greatly reduced, and the metal tube wall is prone to overheating and damage due to deteriorated heat transfer. Utility Model Content

[0004] The purpose of this invention is to provide a cross-flow multi-pass steam generator that can effectively prevent heat exchange tubes from overheating and being damaged due to heat transfer deterioration.

[0005] This utility model is implemented as follows: A cross-flow multi-pass steam generator includes a hollow flue. The flue has a steam collecting ring at the upper end and a water collecting ring at the lower end. Inside the flue is an annular heat exchange tube assembly formed by multiple heat exchange tubes, with a flue gas passage gap between adjacent heat exchange tubes. The upper end of each heat exchange tube is connected to the steam collecting ring, and the lower end is connected to the water collecting ring. A baffle is horizontally provided in the middle of the flue. The edge of the baffle is connected to the outer wall of each heat exchange tube, dividing the inner space of the annular heat exchange tube assembly into a low-temperature convection zone and a high-temperature furnace zone distributed vertically. The low-temperature convection zone is located above the high-temperature furnace zone.

[0006] In the aforementioned cross-flow multi-pass steam generator, the top of the flue is provided with a top flue pipe that connects to the low-temperature convection zone.

[0007] In the aforementioned cross-flow multi-pass steam generator, an annular baffle plate is provided on the outer space of the annular heat exchange tube group corresponding to the low-temperature convection zone, dividing it into upper and lower spaces. The inner ring of the annular baffle plate is connected to the outer wall of each heat exchange tube, and the outer ring is connected to the inner wall of the smoke sealing cylinder. The smoke sealing cylinder is provided with a side smoke outlet pipe, which connects to the space above the annular baffle plate.

[0008] In the aforementioned cross-flow multi-pass steam generator, the baffle is circular, and the heat exchange tubes are distributed circumferentially.

[0009] In the above-mentioned cross-flow multi-pass steam generator, the top of the steam collecting ring is provided with a steam outlet, and the side of the water collecting ring is provided with a water inlet.

[0010] In the aforementioned cross-flow multi-pass steam generator, fins are distributed on the outside of the heat exchange tubes.

[0011] In the aforementioned cross-flow multi-pass steam generator, the baffle is located in the middle or upper part of the heat exchange tube.

[0012] In the aforementioned cross-flow multi-pass steam generator, the distance between the baffle and the lower end face of the heat exchange tube is greater than the distance between the baffle and the upper end face of the heat exchange tube.

[0013] The outstanding advantages of this utility model compared to the prior art are: This invention features a horizontally installed baffle in the middle of the flue, with its edge connected to the outer wall of each heat exchange tube. This baffle divides the inner space of the annular heat exchange tube assembly into a low-temperature convection zone and a high-temperature furnace zone, distributed vertically. The heat exchange tubes in the high-temperature furnace zone, being filled with water (which has a high heat transfer coefficient), do not experience heat transfer deterioration. Meanwhile, the low-temperature convection zone, with its low temperature, effectively prevents overheating and damage to the heat exchange tubes due to heat transfer deterioration, thus ensuring the safe operation of the equipment. Simultaneously, the high-temperature furnace zone, located inside the annular heat exchange tube assembly, ensures more uniform heat absorption and a smaller temperature difference among the heat exchange tubes, resulting in uniform thermal stress, a longer service life, and a larger furnace volume, which is beneficial for complete fuel combustion. Attached Figure Description

[0014] Figure 1 This is a structural schematic diagram of Embodiment 1 of this utility model.

[0015] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this utility model.

[0016] Attached reference numerals: 1. Smoke casing; 2. Steam collecting ring; 3. Water collecting ring; 4. Heat exchange tube; 5. Baffle; 6. Low-temperature convection zone; 7. High-temperature furnace zone; 8. Top smoke outlet pipe; 9. Annular smoke baffle; 10. Side smoke outlet pipe; 11. Steam outlet; 12. Water inlet; 13. Fin. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments. See also: Figure 1 —2: Example 1: See Figure 1 : A cross-flow multi-pass steam generator includes a hollow flue 1. The flue 1 has a steam collecting ring 2 at its upper end and a water collecting ring 3 at its lower end. The flue 1 contains an annular heat exchange tube group formed by multiple heat exchange tubes 4, with a flue gas passage gap between adjacent heat exchange tubes 4. The upper end of each heat exchange tube 4 is connected to the steam collecting ring 2, and the lower end is connected to the water collecting ring 3. A baffle 5 is horizontally provided in the middle of the flue 1. The edge of the baffle 5 is connected to the outer wall of each heat exchange tube 4, dividing the inner space of the annular heat exchange tube group into a low-temperature convection zone 6 and a high-temperature furnace zone 7 distributed vertically. The low-temperature convection zone 6 is located above the high-temperature furnace zone 7.

[0018] Figure 1 The arrows indicate the direction of the flue gas, the short horizontal lines represent water, and the small circles represent water vapor.

[0019] Due to the high-temperature heating, the liquid level is higher in actual operation than when it is not heated, and the liquid level fluctuates during actual operation, rather than remaining stable. In this embodiment, the heat absorption section refers to the part below the liquid level line, and the evaporation section refers to the part above the liquid level line, where the liquid level line refers to the liquid level line under high-temperature heating in actual operation.

[0020] The working principle of this utility model is as follows: Figure 1 As shown, after the burner sends fuel and combustion air into the high-temperature furnace zone 7 for combustion, the flue gas enters the outer space of the annular heat exchange tube group through the flue gas gap between two adjacent heat exchange tubes 4. Then it moves upward and enters the low-temperature convection zone 6 through the flue gas gap between two adjacent heat exchange tubes 4. The water in the heat exchange tube 4 absorbs a large amount of heat energy in the heat absorption section and becomes a steam-water mixture that enters the evaporation section to continue absorbing heat and evaporating, finally producing saturated steam.

[0021] After the flue gas cools down by exchanging heat with the heat exchange tubes 4 in the high-temperature furnace zone 7, it enters the low-temperature convection zone 6. Therefore, the temperature of the low-temperature convection zone 6 is lower than that of the high-temperature furnace zone 7.

[0022] This invention features a horizontally installed baffle 5 in the middle of the flue 1. The edge of the baffle 5 is connected to the outer wall of each heat exchange tube 4, dividing the inner space of the annular heat exchange tube group into a low-temperature convection zone 6 and a high-temperature furnace zone 7 distributed vertically. The heat exchange tubes 4 located in the high-temperature furnace zone 7 will not experience heat transfer deterioration because they are filled with water (water has a high heat transfer coefficient). The low-temperature convection zone 6 has a low temperature, effectively preventing the heat exchange tubes 4 from overheating and being damaged due to heat transfer deterioration, thus ensuring the safe operation of the equipment. At the same time, the high-temperature furnace zone 7 is located inside the annular heat exchange tube group, where the heat absorption of each heat exchange tube 4 is more uniform, the temperature difference is smaller, the thermal stress of the heat exchange tubes 4 is uniform, the service life of the equipment is longer, and the volume of the furnace can be arranged to be larger, which is conducive to the complete combustion of fuel.

[0023] This invention rationally arranges the heat absorption section and evaporation section of the heat exchange tube 4 according to the high and low external heat load, effectively improving the safety of the equipment.

[0024] Furthermore, the top center of the flue duct 1 is provided with a top flue pipe 8 that connects to the low-temperature convection zone 6. The flue gas entering the low-temperature convection zone 6 is discharged through the top flue pipe 8, forming a two-pass heat exchange. To increase the volume of the furnace chamber, the baffle 5 is circular, and the heat exchange tubes 4 are distributed circumferentially. In this embodiment, the heat exchange tubes 4 are evenly distributed circumferentially.

[0025] Furthermore, the top of the steam collecting ring 2 is provided with a steam outlet 11, and the side of the water collecting ring 3 is provided with a water inlet 12. The water pump sends softened water into the water inlet 12, and the softened water enters the heat absorption section of each heat exchange tube 4 through the water collecting ring 3, and then enters the evaporation section, turning the water into saturated steam, which is then sent into the gas pipeline through the steam collecting ring 2 and the steam outlet 11.

[0026] To increase the heat exchange area of ​​the heat exchange tube 4, fins 13 are distributed on the outside of the heat exchange tube 4.

[0027] Furthermore, the baffle 5 is disposed in the middle or upper part of the heat exchange tube 4.

[0028] Preferably, the distance between the baffle 5 and the lower end face of the heat exchange tube 4 is greater than the distance between the baffle 5 and the upper end face of the heat exchange tube 4.

[0029] This utility model is not classified as a special equipment exempt from inspection; it is an inspection-exempt product. It is small in size, its installation location is not limited, and it can be installed in confined spaces such as stairwells, rooftops, and basements. It is small in size and has low material costs. No separate equipment room is required, resulting in low initial investment.

[0030] Example 2: See Figure 2 : This embodiment is basically the same as the structure of the first embodiment above. The main difference is that: the outer space of the annular heat exchange tube group corresponding to the low temperature convection zone 6 is provided with an annular smoke baffle 9 that divides it into upper and lower spaces. The inner ring of the annular smoke baffle 9 is connected to the outer wall of each heat exchange tube 4, and the outer ring is connected to the inner wall of the smoke sealing cylinder 1. The side of the smoke sealing cylinder 1 is provided with a side smoke outlet pipe 10, which connects to the space above the annular smoke baffle 9.

[0031] After entering the low-temperature convection zone 6, the flue gas passes through the flue gas gap between two adjacent heat exchange tubes 4 and enters the outer space of the annular heat exchange tube group. It is then discharged from the side flue gas outlet pipe 10, forming a three-pass heat exchange. This increases the flue gas flow path, lowers the flue gas temperature, and greatly improves the thermal efficiency of the equipment, achieving the goal of energy saving and emission reduction.

[0032] The above embodiments are only one of the preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes made in accordance with the shape, structure and principle of this utility model should be covered within the protection scope of this utility model.

Claims

1. A cross-flow multi-pass steam generator, characterized in that: The device includes a hollow smoke-sealing duct (1), with a steam collecting ring (2) at the upper end and a water collecting ring (3) at the lower end. Inside the smoke-sealing duct (1) is an annular heat exchange tube group formed by multiple heat exchange tubes (4), with a smoke passage gap between two adjacent heat exchange tubes (4). The upper end of the heat exchange tube (4) is connected to the steam collecting ring (2), and the lower end is connected to the water collecting ring (3). A baffle (5) is horizontally provided in the middle of the smoke-sealing duct (1), with the edge of the baffle (5) connected to the outer wall of each heat exchange tube (4), and dividing the inner space of the annular heat exchange tube group into a low-temperature convection zone (6) and a high-temperature furnace zone (7) distributed vertically. The low-temperature convection zone (6) is located above the high-temperature furnace zone (7).

2. The cross-flow multi-pass steam generator according to claim 1, characterized in that: The top of the smoke-sealing cylinder (1) is provided with a top smoke outlet pipe (8) that connects to the low-temperature convection zone (6).

3. The once-through multi-pass steam generator according to claim 1, characterized in that: The outer space of the annular heat exchange tube group corresponding to the low temperature convection zone (6) is provided with an annular smoke baffle (9) that divides it into upper and lower spaces. The inner ring of the annular smoke baffle (9) is connected to the outer wall of each heat exchange tube (4), and the outer ring is connected to the inner wall of the smoke sealing cylinder (1). The side of the smoke sealing cylinder (1) is provided with a side smoke outlet pipe (10), and the side smoke outlet pipe (10) connects to the space above the annular smoke baffle (9).

4. A cross-flow multi-pass steam generator according to claim 1, characterized in that: The baffle (5) is circular, and the heat exchange tubes (4) are distributed in a circular pattern.

5. A cross-flow multi-pass steam generator according to claim 1, characterized in that: The steam collecting ring (2) has a steam outlet (11) at the top and a water inlet (12) on the side of the water collecting ring (3).

6. A cross-flow multi-pass steam generator according to claim 1, characterized in that: The heat exchange tube (4) has fins (13) distributed on its outside.

7. A cross-flow multi-pass steam generator according to claim 1, characterized in that: The baffle (5) is located in the middle or upper part of the heat exchange tube (4).

8. A cross-flow multi-pass steam generator according to claim 7, characterized in that: The distance between the baffle (5) and the lower end face of the heat exchange tube (4) is greater than the distance between the baffle (5) and the upper end face of the heat exchange tube (4).

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